Re: Which is more Efficient in STL ------ SET / MAP ?

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 14 Feb 2008 02:05:16 -0800 (PST)

Message-ID:

<47bfe89f-ca0e-4fa9-b5bc-6d858b296900@d21g2000prf.googlegroups.com>

On Feb 13, 7:10 pm, Jeff Schwab <j...@schwabcenter.com> wrote:

Pallav singh wrote:

Which is more Efficient in STL ------ SET / MAP ?

as in SET we can use insert( ) function which allow to insert at a
given Iterator position

The position is just a hint.

( if Element is passed by comparator
function )........

How would the comparator ever reject an element? By throwing
an exception?

I have a Doubt that does not it harm Search time
Complexity in SET???

The complexity of insertions should be amortized log(N) with
the size of the set. If you consistently give the worst
possible hint (e.g. using set_.begin() to insert elements that
belong at the end of the set), I suppose the complexity might
be affected in an implementation-specific manner. (Or not.)

It shouldn't be. Concerning the complexity of this function,
the standard says "logrithmic in general, but amortized constant
if t is inserted right before p" (t is the element being
inserted, p is the hint). Roughly speaking, the function checks
whether t should be inserted immediately before p, and if not,
simply ignores the hint, and calls the insert without the hint.

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